There are many situations were medical equipment, such as sonogram devices, must be used in a sterile environment. When such equipment is used in a sterile environment the person using the equipment (a sonographer in the case of sonographic devices) must from time to time interact with the device controls for a variety of reasons. However, because of the sterile conditions the sonographer must have a method of interaction with the equipment that will not compromise the sterile environment.
Some areas of particular concern occurs when sonography is used for assisting with nerve blocks and peripherally inserted central catheter (PICC) lines both of which procedures must be performed in sterile environments. Thus, the patient is sterile, the doctor and nurses are sterile, but the sonograph machine is sitting a way from the sterile zone and is not sterile. If the operator were to touch the machine, as would occur in order to manually adjust a dial or operate a switch, the operator would no longer be sterile. Since various machine operations, such as depth and gain adjustments, must occur during the procedure the operator must interact with the sonogram machine several times during the course of a procedure.
One method for dealing with this issue is to use a second person who physically interacts with the machine outside of the sterile zone based upon instructions given by a person within the sterile zone. Using two people is costly and inefficient.
One method of eliminating the second person is for the person in the sterile environment to use a fresh sterile gauze pad (usually a 4×4 pad) every time the sonogram machine is to be touched. This presupposes that a stack of such sterile pads are available (which requires planning and prior execution) and also presupposes that the operator can reach the machine, which sometimes is positioned across the patient and sometimes several yards from the patient.